The overall objective of our laboratory is best described as the collection of data concerning nervous and endocrine system functioning and behavior as they influence and interact with the aging process in mammalian organisms. To this end we are conducting experiments with laboratory rats attempting to identify neural structures involved in the mediation of sexual behavior, and to describe how these structures and their functioning change with age. Further, we are attempting to identify and describe endocrine events which modify the expression and time change course of sexual behavior.